26 November 2012

Nov 26, 2012

Parts of New South Wales, especially the east will record the warmest run of weather since the Summer of 2010/11. Sydney has already recorded warmer days this Spring than for the entire summer of 2011/12. Temperatures through this week will remain well above average with a peak expected Friday and Saturday where on both days most of the state away from the very coastal fringe and ranges will reach close to or exceed 40 degrees ahead of a milder change on Sunday. Towns in the states north west and west could experience maximums in the low to 40 degree range today, Thursday, Friday and Saturday.

The weather pattern this week will draw warm and humid air across most of the state as an almost stationary high sits in the Tasman Sea. The atmosphere over most of the state will be relatively unstable as a trough extends from the north west to the south east triggering mostly isolated afternoon and evening showers and thunderstorms along the ranges and nearby slopes. There is the potential that some of these thunderstorms could become severe mostly along the ranges.

Parts of the central and southern ranges could collect falls in the 10 to 20mm range on Tuesday with the southern half of the northern tablelands looking at similar falls on Wednesday. Falls on other days do not look significant at this stage.

At this stage the strongest winds are more likely along the coast in association with afternoon sea breezes. The weather pattern is not expected to trigger widespread winds above about 20 knots over the land.

A broadly unstable atmosphere in association with a series of troughs and high heat will trigger the potential for showers and thunderstorms most days of this week and into the weekend through parts of the continent and there is a fairly high potential for severe thunderstorms development. In contrast fresh onshore winds and a series of cold fronts will keep the South West Land Division of Western Australia much cooler and showery.

A trough currently in the south east will trigger isolated showers and thunderstorms today, Tuesday and Wednesday with another trough entering the region Thursday and Friday. Temperatures will remain warm to hot ahead of the second trough which once it moves through milder air will move into the south east. Rainfall from showers and thunderstorms will be patchy with Tuesday the better of the days for falls of 5 to 15mm about the eastern half of Victoria and southern and central ranges and south coast of New South Wales.

The western half of the Northern Territory and eastern Kimberley region of Western Australia will record the better of the falls through the week with widespread accumulated totals of 25 to 50mm with daily showers and thunderstorms. The South West coast will also record widespread falls of 10 to 30mm with isolated heavier totals as cold fronts and a low cross through the region but these better falls will not stretch to inland regions of the south west..

A trough extending from the north of Western Australia to the south of the state will be captured by several cold fronts sweeping into the south west and be drawn towards the eastern states by Thursday. A band of mostly light showers and thunderstorms will develop ahead of the trough but at this stage the southern half of this system looks unlikely to trigger widespread worthwhile rainfall although there could be some isolated better totals. Severe thunderstorms could be possible with this trough.

Queensland, South Australia and Tasmania are looking at very little rainfall with a hot week across Queensland and South Australia and mild to warm across Tasmania.